Embodiments of the invention are directed, in general, to positioning systems and, more specifically, wireless probes and Wi-Fi positioning.
As mobile devices proliferate, the demand for services tailored to device location also increases. Location based services depend on positioning systems to determine device location. Satellite based position systems, such as the global positioning system (GPS), GLONASS, and Galileo can provide high accuracy, but require a clear line of sight between the satellites and the mobile device to provide a position determination. Consequently, satellite positioning systems are largely ineffective for indoor positioning. Satellite positioning also requires specialized receivers that may increase the cost of the mobile device.
As an alternative or an augmentation to satellite based positioning, wireless local area network (WLAN) based positioning systems have been developed. WLAN based positioning systems are suitable for indoor positioning and require minimal investment because they make use of existing infrastructure. Furthermore, many mobile wireless devices include support for communication via WLAN.
WLAN based positioning systems determine mobile device position based on the established positions of WLAN access points visible to the device and the strength of signals exchanged between the mobile device and the access points.
Most smartphones use WiFi for positioning. Beacon and/or probe requests and responses may be used to improve positioning of smartphones. However, probe requests and responses sent from smartphones may need improvement in positioning accuracy which results in lower throughput for other devices in the network. This is due to the fact that probe requests and probe responses are sent at low legacy rates and they carry large payloads. What is needed are modified payloads for probe requests and responses without breaking interoperability in the network. The probe requests and responses may still be of the same frame type.